U.S. patent number 4,545,565 [Application Number 06/622,739] was granted by the patent office on 1985-10-08 for diaphragm valve.
This patent grant is currently assigned to Asahi Yukizai Kogyo Co., Ltd.. Invention is credited to Nichiro Sano, Kazuhiko Tsuno.
United States Patent |
4,545,565 |
Sano , et al. |
October 8, 1985 |
Diaphragm valve
Abstract
A diaphragm valve suitable for the food industry, including a
valve body (1) and body caps (2) connected to opposite ends thereof
in a detachable but water-tight manner. Sealing between the valve
body (1) and the body cap (2) is provided by an annular groove (16)
recessed on the end surface of the valve body (1) and/or the body
caps (2) and packing rings (17) having an inner diameter
corresponding to that of the valve body (1) and provided with an
annular protrusion (18) fitted to the groove (16). By this sealing,
a gap between the opposite surfaces of the valve body (1) and the
body cap (2) is completely eliminated.
Inventors: |
Sano; Nichiro (Nobeoka,
JP), Tsuno; Kazuhiko (Nobeoka, JP) |
Assignee: |
Asahi Yukizai Kogyo Co., Ltd.
(JP)
|
Family
ID: |
16226209 |
Appl.
No.: |
06/622,739 |
Filed: |
June 20, 1984 |
Foreign Application Priority Data
|
|
|
|
|
Dec 8, 1983 [JP] |
|
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58-188583[U] |
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Current U.S.
Class: |
251/331;
285/336 |
Current CPC
Class: |
F16K
7/126 (20130101); F16J 15/062 (20130101); F16J
15/061 (20130101) |
Current International
Class: |
F16K
5/00 (20060101); F16K 7/12 (20060101); F16K
7/16 (20060101); F16K 5/20 (20060101); F16K
5/06 (20060101); F16K 007/16 (); F16L 017/06 () |
Field of
Search: |
;285/336 ;251/331 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Rosenthal; Arnold
Attorney, Agent or Firm: Burns, Doane, Swecker &
Mathis
Claims
We claim:
1. A diaphragm valve comprising a valve body having an upstream and
a downstream end, a body cap on each said upstream and downstream
end, piping on each said end, a diaphragm means for controlling a
rate of liquid flow through the valve located intermediate each
said end and means for providing a water-tight seal between said
valve body and said body caps comprising an annular groove recessed
in an end surface of each end of one of said valve body and a body
cap, and packing rings each having an annular base with an annular
protrusion on a surface of said annular base fitting into each of
said annular grooves; each said protrusion having a cross-sectional
configuration in the shape of a rectangle connected by a converging
trapezoid to said base surface, and each said packing ring having
an inner diameter equal to the inner diameter of said valve
body.
2. A diaphragm valve according to claim 1, wherein said valve body
is mainly made of polyvinyl chloride.
3. A diaphragm valve according to claim 1, wherein said annular
groove is recessed on the respective end surface of said valve
body.
4. A diaphragm valve according to claim 1, wherein said annular
groove is recessed on an end surface of said body cap.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a diaphragm valve made of plastic
and suitably utilized in the food industry for controlling
transportation of a liquid.
2. Description of the Prior Art
A diaphragm valve comprising a valve body provided on each side
thereof with a body cap by means of a cap nut threadedly engaged
thereto is well known in the art. This type of the disphragm valve
usually has a sealing means between the valve body and the body
caps consisting of an annular groove recessed on the end surface of
the body or the caps and an O-ring engaged in the groove. Such a
valve has the drawback that a small amount of liquid transported
through the valve tends to remain in the gap between the annular
groove and the O-ring or between the opposed end surfaces of the
body and the caps. This remaining liquid may freeze and expand in
the winter, causing loose sealing. The remaining liquid causes a
further serious problem when the valve is applied in the food
industry because it may putrefy by bacteria and contaminate the
entire system. When the transported liquid is purified water, it
may degrade the purity of the water.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a diaphragm
valve free from the above drawbacks of the prior art.
It is another object of the present invention to provide a
diaphragm valve made of plastic, which has no gap in sealing
between the valve body and body caps and thereby is not liable to
liquid remaining therein.
The above objects of the present invention are achievable by a
diaphragm valve including a valve body provided with a body cap at
each end thereof, the body caps being connectable to an upstream
piping or a downstream piping, and a diaphragm capable of
controlling a rate of liquid flow to be transported through the
valve, water-tight sealing between the valve body and the body caps
being provided by means of packing rings accommodated in an annular
groove or grooves recessed on the opposed end surface of the valve
body and/or the body caps, characterized in that the packing rings
have the same inner diameter as that of the valve body and are
provided with an annular protrusion or protrusions to be
accommodated into the entire length of the annular groove.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the present invention will be
apparent from the description with reference to the attached
drawings in which:
FIG. 1 is a sectional side view of a diaphragm valve of the prior
art;
FIG. 1A is an enlarged view of sealing in a circle A shown in FIG.
1;
FIG. 2 is a similar view as FIG. 1 of one embodiment of the present
invention;
FIGS. 3 and 4 are enlarged side sectional views showing two
different types of sealing according to the present invention;
and
FIG. 5 is a perspective view of part of a preferable packing ring
according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
At first, the prior art will be described in more detail with
reference to FIGS. 1 and 1A for better understanding of the present
invention.
A typical conventional diaphragm valve, as shown in FIG. 1,
includes a valve body 1 and two body caps 2, 2. The valve body 1 is
essentially a hollow tube made of plastic such as polyvinyl
chloride. The body caps 2 are tightly secured to ends of the valve
body 1 by means of cap nuts 3, which are threadedly engageable with
an outer surface of the valve body 1. The valve can be incorporated
in a pipeline (not shown) in a known manner. The valve body 1 can
solely be removed therefrom by disengagement of the cap nuts 3 from
the valve body 1, if necessary.
Part of an inside wall of the valve body 1 projects inward at a
midportion thereof and forms a shutter wall 4. An opening 5 is
provided on a side wall of the valve body 1 confronting the shutter
wall 4. A diaphragm 6 made of a resilient material such as
synthetic rubber or plastic is mounted on a flange 7 provided
around the opening 5 so as to seal the opening 5 in a manner
described later. Thus, the shutter wall 4 and the diaphragm 6 are
positioned to confront each other.
A presser 8 is secured on the midportion of the diaphragm 6 through
a metal member 9 embedded therein. The presser 8 is made of a rigid
material such as metal or hard plastic and has a function to deform
the diaphragm 6 so as to bring it into contact with the shutter
wall 4 when stopping of the liquid flow is required.
Further, a bonnet 10 rests on the diaphragm 9 at the outerside of
the presser 8 through a metal liner 11 and is secured on the valve
body 1 by means of screw-nut means (not shown), whereby the
diaphragm 6 is fixedly nipped between the bonnet 10 and the flange
7.
A spindle 12 is coaxially fixed at the lower end thereof to the
presser 8 and further is supported at the middle portion by a
sleeve 13 threadedly engaged with the spindle 12. On the other
hand, the sleeve 13 is coaxially mounted on the bonnet 10 so as to
be slidable both in the rotational and the axial directions
relative to the bonnet 10.
A handle 14 is fixed to the sleeve 13 for rotation thereof.
According to the above-mentioned constructions, rotation of the
handle 14 causes the sleeve 13 to revolve and, in turn, the spindle
12 threadedly engaged thereto is displaced in the axial
direction.
Each body cap 2 has a stepped channel, comprising a first channel
at a side to be adjacent to the valve body 1 having the same
diameter "d" as that of the valve body 1 and a second channel at
the other side further from the valve body 1 having a larger
diameter than the former.
The sealing between the valve body 1 and each of the body caps 2 is
attained by an O-ring 15 located in an annular groove 16 recessed
on the end surface of the valve body 1 to be adjacent to the body
caps 2. As apparent from FIG. 1A, a gap H is inherently formed
between the opposed surfaces of the valve body 1 and the body caps
2, in which part of the liquid is trapped and causes the trouble
described before.
To solve this problem, a diaphragm valve according to the present
invention is proposed as shown in FIG. 2. This valve has
essentially the same construction as the one illustrated in FIG. 1
except for the sealing between the valve body and the body caps
and, therefore, the same reference numerals are utilized for
designating similar or identical parts of the two.
Instead of the O-ring 15 utilized in the conventional valve, there
is adopted a packing ring 17 which has an inner diameter "d" the
same as those of the channel of the valve body 1 and of the first
channel of the body caps 2 and also has an annular protrusion 18
adapted to be tightly accommodated in the entire length of annular
groove 16. The packing ring 17 may be made of any resilient
material, but preferably is an elastomer. A height of the
protrusion 18 from a base surface 21 of the packing ring 17 is
preferably somewhat larger than the depth of the groove 16, such as
from 0.2 mm to 0.3 mm.
The annular groove 16 may be provided on the end surface of the
body caps 2 instead of or in addition to the end surface of the
valve body 1 as shown in FIG. 3 or 4. In such cases, of course, the
packing ring 17 should have a protrusion or protrusions having a
cross-section corresponding to those of the grooves.
The cross-section of the protrusion 18 may be of any shape, such
rectangular or semi-circular, provided good sealing can be
obtained. However, it has been found that one consisting of a
rectangle 19 connected by a converged trapezoid 20 to the base
surface 21 of the packing ring 17 is the most preferable. This is
because a space 22 created between the converged trapezoid 20 and
the inner wall of the groove 16 can accommodate the expanded
portion of the packing ring 17 caused by deformation when the ring
17 is pressed into the groove 16 by the threading engagement of the
cap 2 with the valve body 1, whereby a further tight seal can be
achieved. Of course, another protrusion may be provided on the
oppsite side of the packing ring for use of the seal of the type
shown in FIG. 3.
As stated above, according to the present invention, there is no
gap between the opposed end surfaces of the valve body 1 and of the
body cap 2, which gap often occurs in a conventional valve, whereby
the above problems can be eliminated.
* * * * *